Compile with warnings as errors in CI (backport #1103)

[mergify]

Description

Fast DDS Docs CI does not compile with warnings as errors enabled, so relevant warnings (e.g: deprecation warnings) are ignored. This PR fixes it.

@Mergifyio backport 3.3.x 3.2.x 2.14.x

Merge after:

• Fix deprecation warning in CustomChainingTransport #1104

Contributor Checklist

• Commit messages follow the project guidelines.
• N/A Code snippets related to the added documentation have been provided.
• _N/A: Documentation tests pass locally.
• Applicable backports have been included in the description.

Reviewer Checklist

• The PR has a milestone assigned.
• The title and description correctly express the PR's purpose.
• Check contributor checklist is correct.
• CI passes without warnings or errors.

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This is an automatic backport of pull request #1103 done by [Mergify](https://mergify.com).